Geoscience Reference
In-Depth Information
B&W Aerial Photo
LANDSAT TM Image
(b)
CIR Aerial Photo
LANDSAT TM Image
(c)
CIR Aerial Photo
LANDSAT TM Image
Plate 7.1
(See color insert following page 114.) (a) Heterogeneity problem: reference site consists of
several classes. (b) LC class changed between acquisition dates in reference site. (c) Ambiguity
of class definitions; it is difficult to differentiate between high-density and commercial class
according to definition.
example, when the reference site was on the shadowy side of a mountain, it was impossible to see
the reference features except the ridgeline of the mountain; thus, the interpreter was required to
locate the reference site based on the approximate distance to and the direction of the ridgeline.
The third case was the most common source of confusion in the interpretation process. Reference
sites were frequently on the border of two or more classes. In these situations, the interpreter
